1. Field of the Invention
The present invention relates to a work loading and unloading device for a bending machine, and more specifically to a device for loading work to a bending machine such as a press brake and further for unloading the bent work from the same bending machine.
2. Description of the Related Art
In the conventional work loading and unloading device for loading work to a bending machine such as a press brake and further for unloading out the bent work from the bending machine, a robot with a 6-axis control is fixedly arranged on the front side of a single bending machine, independently. In addition, the upper and lower hands openable to both sides are attached to a work hand of the robot.
In the above-mentioned conventional 6-axis control robot, however, there exists a problem in that the cost of the robot itself is high and further a long program preparation and teaching time (i.e., the setup time) is needed. In addition, since the conventional work loading and unloading device must be arranged for each bending machine separately, it is troublesome to use the same work loading and unloading device for the other bending machines.
Further, in the conventional work loading and unloading device, when work is brought into contact with a back gage, since the work hand brings the work toward and near the back gage under clamped condition, in the case where a small-sized work is brought into contact with the back gage under clamped condition, there exists a problem in that the work hand interferes with a die, before the work is brought into contact with the back gage. Further, when the already bent work is clamped by the work hand, since the work hand also interferes with the die, the moving stroke of the work hand must be reduced. However, since the work hand is not provided with a double-work take-up detecting device, the double-work taking-up must be detected on the work loading device side, so that it takes a relatively long time to detect the double work taking-up.